Ethernet is a shared network, meaning that many different machines can connect to the same Ethernet and can communicate directly with each other. I’m going to assume that you’re using Ethernet as found in an average office or datacenter. Also, although Ethernet has been implemented over many different physical media, I’ll assume you’re working with CAT5 or better cable—today’s most popular choice. If you use some unusual media type, or your card supports multiple media, you might need to manually set your preferred media on your interface.
Protocol and Hardware
Ethernet is a broadcast protocol, which means that every packet you transmit can be sent to every host on the network (although most Ethernet hardware limits recipients). ...